When a person's heart stops beating on its own, blood circulation sufficient to maintain life can be obtained by periodically compressing the heart through a physical force being applied to the chest. Such methods of compressing the chest to create blood flow through the heart is an essential part of cardiopulmonary resuscitation (C.P.R.). The proper application of force applied to a person's chest and the rate of compression/decompression are largely governed by the physical characteristics of the person receiving C.P.R. For instance, the force used to compress the chest of a small child differs greatly from the force used to compress the chest of a large adult. If the amount of force used in administering C.P.R. is insufficient to properly compress the heart, the patient's blood flow would be inadequate and the patient may suffer brain damage or may fail to be resuscitated. Alternatively, if too much force is applied to a patient's chest, the patient may suffer significant injury such as injury to vital organs, broken ribs and/or internal bleeding.
The administration of C.P.R. also requires mouth-to-mouth resuscitation to be used in addition to cardiac compression. Mouth-to-mouth resuscitation fills the lungs with air and provides oxygen to the blood, while the cardiac compression circulates the newly oxygenated blood throughout the body. During ideal circumstances, C.P.R. is administered by two people. One person performs the repeated cardiac compression while the other person periodically performs the needed mouth-to-mouth resuscitation and monitors the vital signs of the patent. The problem with administering emergency C.P.R. is that circumstances are typically far from ideal. In a situation, such as an accident or a heart attack, C.P.R. is often administered by a single person in an environment of confusion and near panic. In this confusing environment, the person administering C.P.R. must remember how and where to perform chest compression, how hard to compress the chest for any given patient, how many times per minute to perform the chest compressions and how often to stop the chest compressions in order to administer mouth-to-mouth resuscitation. All of this information is hard to remember for even professional rescue workers, however, it is much more difficult to remember by a bystander that may have only had C.P.R. training once or twice in his or her life.
The prior art is replete with devices that can be used to help teach and/or administer C.P.R. to a patient. Many such prior art devices take away much of the guess work involved in administering C.P.R. by prompting the person administering C.P.R. to take various actions at the appropriate times. Examples of such prior art references are as follows.
U.S. Pat. No. 4,863,385 to Pierce, entitled CARDIOPULMONARY RESUSCITATION SEQUENCER and issued Sep. 5, 1989, shows a compact portable computer for assisting in the application of C.P.R. The Pierce device has variable inputs that allows a person to input the physical size of the patent. The Pierce device then visually and audibly informs a person as to when to apply cardiac compression and when to administer mouth-to-mouth resuscitation.
U.S. Pat. No. 4,077,400 to Harrigan, and its progeny U.S. Pat. Nos. 4,095,590; 4,166,458; and 4,237,872 all entitled EXTERNAL CARDIAC RESUSCITATION AID all show devices that are placed on a patient's chest that assist in the administration of C.P.R. The disclosures of these Harrigan patents disclose the use of pressure gauges, and various audio and visual indicators that help instruct a person in how to properly administer C.P.R. These patents also show the use of an external blood pressure mounting device such as a cuff or wrapping that is wrapped around an extremity of the patient receiving C.P.R.
The purpose of C.P.R. is to artificially cause oxygenated blood to flow through the body when the heart and lungs stop working on their own. However, even if C.P.R. is administered in a textbook fashion, there is no guarantee that enough blood will flow through the body to maintain life in the patient. As has been previously explained, C.P.R. is often administered by a single undertrained person in a highly stress-filled and confusing environment. In such an environment, the person administering C.P.R. cannot stop to check blood flow in the patient. This is because the blood only flows during C.P.R. and stops when the C.P.R. stops. As such, a single person can only assume that he or she is properly administering C.P.R. since a single person cannot administer C.P.R. and check blood flow at the same time.
A need exists in the art for a device that helps a person administer C.P.R., wherein the device provides a dynamic readout of the patient's blood flow rate during the administration of C.P.R. By producing a dynamic display of a patient's blood flow rate, the person administering the C.P.R. can see if the C.P.R. is working on the patient. As a result, the person administering the C.P.R. can make adjustments, such as pushing harder or more frequently than normal to optimize the blood flow rate in that particular patient.
It is therefore an object of the present invention to provide an improved device that assists in the administration of C.P.R. by visually and audibly prompting a person to optimally perform C.P.R.
It is yet another object of the present invention to provide such a device with dynamic display that shows blood flow rate, thereby allowing the person administering C.P.R. to adjust his/her technique to optimize blood flow.